That is a 2-Ton condenser for a mere 800-sq.ft. in a dry climate, it should handle that heatload with ease! If the interior of your home has a low humidity, a mere 90-F outdoors is not a heavy load on that system - when it is operating properly. A room temperature of 76-F should not be difficult to achieve with a very moderate electric usage.
I cool over 800-Sq.Ft in an old 1930's home with a lot of windows with a mere Half-Ton window unit. Your unit is rated at 4 Times the BTUH and mine will pull the temperature down to 76-F with outdoor Heat Index at
104-F.Check my pages & use a thermometer to get all the needed readings. Post the data. There may be some useful clues in that test data. Do the outdoor condenser Temp-Split, it can also be helpful. - udarrell